None is not an integer

from __future__ import division

from __future__ import unicode_literals

import random

__author__ = "Bharath Ramsundar, Aneesh Pappu "

__copyright__ = "Copyright 2016, Stanford University"

__license__ = "MIT"

    Splits internal compounds randomly into train/validation/test.

    """

    np.testing.assert_almost_equal(frac_train + frac_valid + frac_test, 1.)

    if not seed is None:

    if seed is None:

      seed = random.randint(0, 2**30)

    np.random.seed(seed)

    num_datapoints = len(dataset)